#if __GLASGOW_HASKELL__ >= 701
{-# LANGUAGE Trustworthy #-}
#endif
-----------------------------------------------------------------------------
-- |
-- Module      :  System.Win32.Registry
-- Copyright   :  (c) Alastair Reid, 1997-2003
-- License     :  BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer  :  Esa Ilari Vuokko <ei@vuokko.info>
-- Stability   :  provisional
-- Portability :  portable
--
-- A collection of FFI declarations for accessing the Win32 registry.
--
-----------------------------------------------------------------------------

module System.Win32.Registry
		( module System.Win32.Registry
		) where
{- What's really on offer:
	(
	  regCloseKey        -- :: HKEY -> IO ()
	, regConnectRegistry -- :: Maybe String -> HKEY -> IO HKEY
	, regCreateKey       -- :: HKEY -> String -> IO HKEY
	, regCreateKeyEx     -- :: HKEY -> String -> String
	                     -- -> RegCreateOptions -> REGSAM
			     -- -> Maybe LPSECURITY_ATTRIBUTES
			     -- -> IO (HKEY, Bool)
        , regDeleteKey       -- :: HKEY -> String -> IO ()
	, regDeleteValue     -- :: HKEY -> String -> IO ()
	, regEnumKeys	     -- :: HKEY -> IO [String]
	, regEnumKey 	     -- :: HKEY -> DWORD -> Addr -> DWORD -> IO String
	, regEnumKeyValue    -- :: HKEY -> DWORD -> Addr -> DWORD -> Addr -> DWORD -> IO String
	, regFlushKey        -- :: HKEY -> IO ()
	, regLoadKey         -- :: HKEY -> String -> String -> IO ()
	, regNotifyChangeKeyValue -- :: HKEY -> Bool -> RegNotifyOptions
				  -- -> HANDLE -> Bool -> IO ()
	, regOpenKey         -- :: HKEY -> String -> IO HKEY
	, regOpenKeyEx 	     -- :: HKEY -> String -> REGSAM -> IO HKEY
	, regQueryInfoKey    -- :: HKEY -> IO RegInfoKey
	, regQueryValue      -- :: HKEY -> Maybe String -> IO String
	, regQueryValueKey   -- :: HKEY -> Maybe String -> IO String
	, regQueryValueEx    -- :: HKEY -> String -> Addr -> Int -> IO RegValueType
	, regReplaceKey      -- :: HKEY -> String -> String -> String -> IO ()
	, regRestoreKey      -- :: HKEY -> String -> RegRestoreFlags -> IO ()
	, regSaveKey         -- :: HKEY -> String -> Maybe LPSECURITY_ATTRIBUTES -> IO ()
	, regSetValue        -- :: HKEY -> String -> String -> IO ()
	, regSetValueEx      -- :: HKEY -> String -> RegValueType -> LPTSTR -> Int -> IO ()
	, regSetStringValue  -- :: HKEY -> String -> String -> IO ()
	, regUnloadKey       -- :: HKEY -> String -> IO ()
	) where
-}

{-
 Registry API omissions:

   RegQueryMultipleValues()
   RegEnumKeyEx()

-}

import System.Win32.Time
import System.Win32.Types
import System.Win32.File

import System.IO.Unsafe
import Foreign hiding (unsafePerformIO)

#include <windows.h>

#{enum HKEY, (unsafePerformIO . newForeignHANDLE . castUINTToPtr)
 , hKEY_CLASSES_ROOT    = (UINT)HKEY_CLASSES_ROOT
 , hKEY_CURRENT_CONFIG  = (UINT)HKEY_CURRENT_CONFIG
 , hKEY_CURRENT_USER    = (UINT)HKEY_CURRENT_USER
 , hKEY_LOCAL_MACHINE   = (UINT)HKEY_LOCAL_MACHINE
 , hKEY_USERS           = (UINT)HKEY_USERS
 }
-- , PKEYERFORMANCE_DATA  NT only
-- , HKEY_DYN_DATA     95/98 only

regCloseKey :: HKEY -> IO ()
regCloseKey key =
  withForeignPtr key $ \ p_key ->
  failUnlessSuccess "RegCloseKey" $ c_RegCloseKey p_key
foreign import stdcall unsafe "windows.h RegCloseKey"
  c_RegCloseKey :: PKEY -> IO ErrCode

-- Connects to a predefined registry handle on another computer.

regConnectRegistry :: Maybe String -> HKEY -> IO HKEY
regConnectRegistry mb_machine key =
  withForeignPtr key $ \ p_key ->
  maybeWith withTString mb_machine $ \ c_machine ->
  alloca $ \ p_out_key -> do
  failUnlessSuccess "RegConnectRegistry" $
    c_RegConnectRegistry c_machine p_key p_out_key
  p_new_key <- peek p_out_key
  newForeignHANDLE p_new_key
foreign import stdcall unsafe "windows.h RegConnectRegistryW"
  c_RegConnectRegistry :: LPCTSTR -> PKEY -> Ptr PKEY -> IO ErrCode

regCreateKey :: HKEY -> String -> IO HKEY
regCreateKey key subkey =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  alloca $ \ p_out_key -> do
  failUnlessSuccess "RegCreateKey" $
    c_RegCreateKey p_key c_subkey p_out_key
  p_new_key <- peek p_out_key
  newForeignHANDLE p_new_key
foreign import stdcall unsafe "windows.h RegCreateKeyW"
  c_RegCreateKey :: PKEY -> LPCTSTR -> Ptr PKEY -> IO ErrCode

type RegCreateOptions = DWORD

#{enum RegCreateOptions,
 , rEG_OPTION_NON_VOLATILE      = REG_OPTION_NON_VOLATILE
 , rEG_OPTION_VOLATILE          = REG_OPTION_VOLATILE
 }

type REGSAM = #{type REGSAM}

#{enum REGSAM,
 , kEY_ALL_ACCESS       = KEY_ALL_ACCESS
 , kEY_CREATE_LINK      = KEY_CREATE_LINK
 , kEY_CREATE_SUB_KEY   = KEY_CREATE_SUB_KEY
 , kEY_ENUMERATE_SUB_KEYS = KEY_ENUMERATE_SUB_KEYS
 , kEY_EXECUTE          = KEY_EXECUTE
 , kEY_NOTIFY           = KEY_NOTIFY
 , kEY_QUERY_VALUE      = KEY_QUERY_VALUE
 , kEY_READ             = KEY_READ
 , kEY_SET_VALUE        = KEY_SET_VALUE
 , kEY_WRITE            = KEY_WRITE
 }

regCreateKeyEx :: HKEY -> String -> String -> RegCreateOptions -> REGSAM -> Maybe LPSECURITY_ATTRIBUTES -> IO (HKEY, Bool)
regCreateKeyEx key subkey cls opts sam mb_attr =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  withTString cls $ \ c_cls ->
  alloca $ \ p_res ->
  alloca $ \ p_disp -> do
  failUnlessSuccess "RegCreateKeyEx" $
    c_RegCreateKeyEx p_key c_subkey 0 c_cls opts sam (maybePtr mb_attr) p_res p_disp
  p_out_key <- peek p_res
  out_key <- newForeignHANDLE p_out_key
  disp <- peek p_disp
  return (out_key, disp == #{const REG_CREATED_NEW_KEY})
foreign import stdcall unsafe "windows.h RegCreateKeyExW"
  c_RegCreateKeyEx :: PKEY -> LPCTSTR -> DWORD -> LPCTSTR -> RegCreateOptions -> REGSAM -> LPSECURITY_ATTRIBUTES -> Ptr PKEY -> Ptr DWORD -> IO ErrCode

regDeleteKey :: HKEY -> String -> IO ()
regDeleteKey key subkey =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  failUnlessSuccess "RegDeleteKey" $ c_RegDeleteKey p_key c_subkey
foreign import stdcall unsafe "windows.h RegDeleteKeyW"
  c_RegDeleteKey :: PKEY -> LPCTSTR -> IO ErrCode

regDeleteValue :: HKEY -> String -> IO ()
regDeleteValue key name =
  withForeignPtr key $ \ p_key ->
  withTString name $ \ c_name ->
  failUnlessSuccess "RegDeleteValue" $ c_RegDeleteValue p_key c_name
foreign import stdcall unsafe "windows.h RegDeleteValueW"
  c_RegDeleteValue :: PKEY -> LPCTSTR -> IO ErrCode

-- XXX Not 100% sure this is right, but I think it is.
-- Surely this function already exists somewhere?
mallocWideChars :: Int -> IO (Ptr a)
mallocWideChars i = mallocBytes (4 * i)

regEnumKeys :: HKEY -> IO [String]
regEnumKeys hkey = do
   hinfo <- regQueryInfoKey hkey
   let buflen = 1+max_subkey_len hinfo
   buf   <- mallocWideChars (fromIntegral buflen)
   ls    <- go 0 buf buflen
   free buf
   return ls
 where
   go n buf buflen = do
      (v,flg)  <- regEnumKey hkey n buf buflen
      if flg /= 0
       then return []
       else do
         vs <- go (n+1) buf buflen
         return (v:vs)

regEnumKeyVals :: HKEY -> IO [(String,String,RegValueType)]
regEnumKeyVals hkey = do
   hinfo <- regQueryInfoKey hkey
   let nmlen  = 1+max_value_name_len hinfo  -- add spc for terminating NUL.
   let vallen = 1+max_value_len hinfo
   nmbuf  <- mallocWideChars (fromIntegral nmlen)
   valbuf <- mallocWideChars (fromIntegral vallen)
   ls     <- go 0 nmbuf nmlen valbuf vallen
   free nmbuf
   free valbuf
   return ls
 where
   go n nmbuf nmlen valbuf vallen = do
      (ty,nm,flg) <- regEnumValue hkey n nmbuf nmlen valbuf vallen
      if flg /= 0
       then return []
       else do

        val <-
	   case ty of
	     x | x == rEG_SZ    -> peekTString (castPtr valbuf)
	       | x == rEG_DWORD -> peekElemOff (castPtr valbuf) 0 >>= \ v -> return (show (v :: DWORD))
	       | otherwise      -> return "<<unknown>>"

        vs <- go (n+1) nmbuf nmlen valbuf vallen
        return ((nm,val,ty):vs)

-- It's up to the programmer to ensure that a large enough
-- buffer is passed in here.

regEnumKey :: HKEY -> DWORD -> LPTSTR -> DWORD -> IO (String, Int)
regEnumKey key index c_name len =
  withForeignPtr key $ \ p_key -> do
  no_more <- failUnlessSuccessOr eRROR_NO_MORE_ITEMS "RegEnumKey" $
    c_RegEnumKey p_key index c_name len
  str <- peekTString c_name
  return (str, fromEnum no_more)
foreign import stdcall unsafe "windows.h RegEnumKeyW"
  c_RegEnumKey :: PKEY -> DWORD -> LPTSTR -> DWORD -> IO ErrCode

regEnumValue :: HKEY -> DWORD -> LPTSTR -> DWORD -> LPBYTE -> DWORD -> IO (RegValueType, String, Int)
regEnumValue key index name name_len value value_len =
  withForeignPtr key $ \ p_key ->
  with name_len $ \ p_name_len ->
  with value_len $ \ p_value_len ->
  alloca $ \ p_reg_ty -> do
  no_more <- failUnlessSuccessOr eRROR_NO_MORE_ITEMS "RegEnumValue" $
    c_RegEnumValue p_key index name p_name_len nullPtr p_reg_ty value p_value_len
  reg_ty <- peek p_reg_ty
  str <- peekTString name
  return (reg_ty, str, fromEnum no_more)
foreign import stdcall unsafe "windows.h RegEnumValueW"
  c_RegEnumValue :: PKEY -> DWORD -> LPTSTR -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> LPBYTE -> Ptr DWORD -> IO ErrCode

eRROR_NO_MORE_ITEMS :: ErrCode
eRROR_NO_MORE_ITEMS = #{const ERROR_NO_MORE_ITEMS}

regFlushKey :: HKEY -> IO ()
regFlushKey key =
  withForeignPtr key $ \ p_key ->
  failUnlessSuccess "RegFlushKey" $ c_RegFlushKey p_key
foreign import stdcall unsafe "windows.h RegFlushKey"
  c_RegFlushKey :: PKEY -> IO ErrCode

-- ifdef FOR_WINDOWS_NT
-- RegGetKeySecurity :: HKEY -> SECURITY_INFORMATION -> IO SECURITY_DESCRIPTION

-- endif

regLoadKey :: HKEY -> String -> String -> IO ()
regLoadKey key subkey file =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  withTString file $ \ c_file ->
  failUnlessSuccess "RegLoadKey" $ c_RegLoadKey p_key c_subkey c_file
foreign import stdcall unsafe "windows.h RegLoadKeyW"
  c_RegLoadKey :: PKEY -> LPCTSTR -> LPCTSTR -> IO ErrCode

-- ifdef FOR_WINDOWS_NT

type RegNotifyOptions = DWORD

#{enum RegNotifyOptions,
 , rEG_NOTIFY_CHANGE_NAME       = REG_NOTIFY_CHANGE_NAME
 , rEG_NOTIFY_CHANGE_ATTRIBUTES = REG_NOTIFY_CHANGE_ATTRIBUTES
 , rEG_NOTIFY_CHANGE_LAST_SET   = REG_NOTIFY_CHANGE_LAST_SET
 , rEG_NOTIFY_CHANGE_SECURITY   = REG_NOTIFY_CHANGE_SECURITY
 }

regNotifyChangeKeyValue :: HKEY -> Bool -> RegNotifyOptions -> HANDLE -> Bool -> IO ()
regNotifyChangeKeyValue key watch notifyFilter event async =
  withForeignPtr key $ \ p_key ->
  failUnlessSuccess "RegNotifyChangeKeyValue" $
    c_RegNotifyChangeKeyValue p_key watch notifyFilter event async
foreign import stdcall unsafe "windows.h RegNotifyChangeKeyValue"
  c_RegNotifyChangeKeyValue :: PKEY -> Bool -> RegNotifyOptions -> HANDLE -> Bool -> IO ErrCode

-- endif

-- for Win 3.x compatibility, use RegOpenKeyEx instead.

regOpenKey :: HKEY -> String -> IO HKEY
regOpenKey key subkey =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  alloca $ \ p_res -> do
  failUnlessSuccess "RegOpenKey" $ c_RegOpenKey p_key c_subkey p_res
  p_res_key <- peek p_res
  newForeignHANDLE p_res_key
foreign import stdcall unsafe "windows.h RegOpenKeyW"
  c_RegOpenKey :: PKEY -> LPCTSTR -> Ptr PKEY -> IO ErrCode

regOpenKeyEx :: HKEY -> String -> REGSAM -> IO HKEY
regOpenKeyEx key subkey sam =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  alloca $ \ p_res -> do
  failUnlessSuccess "RegOpenKeyEx" $ c_RegOpenKeyEx p_key c_subkey 0 sam p_res
  p_res_key <- peek p_res
  newForeignHANDLE p_res_key
foreign import stdcall unsafe "windows.h RegOpenKeyExW"
  c_RegOpenKeyEx :: PKEY -> LPCTSTR -> DWORD -> REGSAM -> Ptr PKEY -> IO ErrCode

data RegInfoKey =
  RegInfoKey {
    class_string       :: String,
    class_id           :: Int,
    subkeys            :: Word32,
    max_subkey_len     :: Word32,
    max_class_len      :: Word32,
    values             :: Word32,
    max_value_name_len :: Word32,
    max_value_len      :: Word32,
    sec_len            :: Int,
    lastWrite_lo       :: Word32,
    lastWrite_hi       :: Word32
  }

regQueryInfoKey :: HKEY -> IO RegInfoKey
regQueryInfoKey key =
  withForeignPtr key $ \ p_key ->
  allocaBytes 100 $ \ c_class_string ->
  alloca $ \ p_class_id ->
  alloca $ \ p_subkeys ->
  alloca $ \ p_max_subkey_len ->
  alloca $ \ p_max_class_len ->
  alloca $ \ p_values ->
  alloca $ \ p_max_value_name_len ->
  alloca $ \ p_max_value_len ->
  alloca $ \ p_sec_len ->
  allocaBytes (#{size FILETIME}) $ \ p_lastWrite -> do
  failUnlessSuccess "RegQueryInfoKey" $
    c_RegQueryInfoKey p_key c_class_string p_class_id nullPtr p_subkeys
        p_max_subkey_len p_max_class_len p_values p_max_value_name_len
        p_max_value_len p_sec_len p_lastWrite
  class_string <- peekTString c_class_string
  class_id <- peek p_class_id
  subkeys <- peek p_subkeys
  max_subkey_len <- peek p_max_subkey_len
  max_class_len <- peek p_max_class_len
  values <- peek p_values
  max_value_name_len <- peek p_max_value_name_len
  max_value_len <- peek p_max_value_len
  sec_len <- peek p_sec_len
  lastWrite_lo <- #{peek FILETIME,dwLowDateTime} p_lastWrite
  lastWrite_hi <- #{peek FILETIME,dwHighDateTime} p_lastWrite
  return $ RegInfoKey
    { class_string = class_string
    , class_id = fromIntegral class_id
    , subkeys = subkeys
    , max_subkey_len = max_subkey_len
    , max_class_len = max_class_len
    , values = values
    , max_value_name_len = max_value_name_len
    , max_value_len = max_value_len
    , sec_len = fromIntegral sec_len
    , lastWrite_lo = lastWrite_lo
    , lastWrite_hi = lastWrite_hi
    }
foreign import stdcall unsafe "windows.h RegQueryInfoKeyW"
  c_RegQueryInfoKey :: PKEY -> LPTSTR -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> Ptr DWORD -> Ptr FILETIME -> IO ErrCode

-- RegQueryMultipleValues :: HKEY -> IO ([VALENT],String)

-- RegQueryValue() isn't really that, it just allows you to
-- get at the default values of keys, so we provide our own
-- (and better!) version of it. If you want RegQueryValue()s
-- behaviour, use regQueryValueKey.

regQueryValueKey :: HKEY -> Maybe String -> IO String
regQueryValueKey key mb_subkey =
  withForeignPtr key $ \ p_key ->
  maybeWith withTString mb_subkey $ \ c_subkey ->
  alloca $ \ p_value_len -> do
  failUnlessSuccess "RegQueryValue" $
    c_RegQueryValue p_key c_subkey nullPtr p_value_len
  value_len <- peek p_value_len
  allocaArray0 (fromIntegral value_len) $ \ c_value -> do
    failUnlessSuccess "RegQueryValue" $
      c_RegQueryValue p_key c_subkey c_value p_value_len
    peekTString c_value
foreign import stdcall unsafe "windows.h RegQueryValueW"
  c_RegQueryValue :: PKEY -> LPCTSTR -> LPTSTR -> Ptr LONG -> IO ErrCode

regQueryValue :: HKEY -> Maybe String -> IO String
regQueryValue key mb_subkey =
  withForeignPtr key $ \ p_key ->
  maybeWith withTString mb_subkey $ \ c_subkey ->
  alloca $ \ p_ty ->
  alloca $ \ p_value_len -> do
  failUnlessSuccess "RegQueryValue" $
    c_RegQueryValueEx p_key c_subkey nullPtr p_ty nullPtr p_value_len
  ty <- peek p_ty
  failUnlessSuccess "RegQueryValue" $ return (if ty == rEG_SZ then 0 else 1)
  value_len <- peek p_value_len
  allocaArray0 (fromIntegral value_len) $ \ c_value -> do
    failUnlessSuccess "RegQueryValue" $
      c_RegQueryValueEx p_key c_subkey nullPtr p_ty c_value p_value_len
    peekTString (castPtr c_value)

regQueryValueEx :: HKEY -> String -> LPBYTE -> Int -> IO RegValueType
regQueryValueEx key name value value_len =
  withForeignPtr key $ \ p_key ->
  withTString name $ \ c_name ->
  alloca $ \ p_ty ->
  with (fromIntegral value_len) $ \ p_value_len -> do
  failUnlessSuccess "RegQueryValueEx" $
    c_RegQueryValueEx p_key c_name nullPtr p_ty value p_value_len
  peek p_ty
foreign import stdcall unsafe "windows.h RegQueryValueExW"
  c_RegQueryValueEx :: PKEY -> LPCTSTR -> Ptr DWORD -> Ptr DWORD -> LPBYTE -> Ptr DWORD -> IO ErrCode

regReplaceKey :: HKEY -> String -> String -> String -> IO ()
regReplaceKey key subkey newfile oldfile =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  withTString newfile $ \ c_newfile ->
  withTString oldfile $ \ c_oldfile ->
  failUnlessSuccess "RegReplaceKey" $
    c_RegReplaceKey p_key c_subkey c_newfile c_oldfile
foreign import stdcall unsafe "windows.h RegReplaceKeyW"
  c_RegReplaceKey :: PKEY -> LPCTSTR -> LPCTSTR -> LPCTSTR -> IO ErrCode

type RegRestoreFlags = DWORD

#{enum RegRestoreFlags,
 , rEG_WHOLE_HIVE_VOLATILE = REG_WHOLE_HIVE_VOLATILE
 , rEG_REFRESH_HIVE     = REG_REFRESH_HIVE
 , rEG_NO_LAZY_FLUSH    = REG_NO_LAZY_FLUSH
 }

regRestoreKey :: HKEY -> String -> RegRestoreFlags -> IO ()
regRestoreKey key file flags =
  withForeignPtr key $ \ p_key ->
  withTString file $ \ c_file ->
  failUnlessSuccess "RegRestoreKey" $ c_RegRestoreKey p_key c_file flags
foreign import stdcall unsafe "windows.h RegRestoreKeyW"
  c_RegRestoreKey :: PKEY -> LPCTSTR -> RegRestoreFlags -> IO ErrCode

regSaveKey :: HKEY -> String -> Maybe LPSECURITY_ATTRIBUTES -> IO ()
regSaveKey key file mb_attr =
  withForeignPtr key $ \ p_key ->
  withTString file $ \ c_file ->
  failUnlessSuccess "RegSaveKey" $ c_RegSaveKey p_key c_file (maybePtr mb_attr)
foreign import stdcall unsafe "windows.h RegSaveKeyW"
  c_RegSaveKey :: PKEY -> LPCTSTR -> LPSECURITY_ATTRIBUTES -> IO ErrCode

-- ifdef FOR_WINDOWS_NT

-- RegSetKeySecurity :: HKEY -> SECURITY_INFORMATION -> SECURITY_DESCRIPTOR -> IO ()

-- endif

-- 3.1 compat. - only allows storage of REG_SZ values.

regSetValue :: HKEY -> String -> String -> IO ()
regSetValue key subkey value =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  withTStringLen value $ \ (c_value, value_len) ->
  failUnlessSuccess "RegSetValue" $
    c_RegSetValue p_key c_subkey rEG_SZ c_value value_len
foreign import stdcall unsafe "windows.h RegSetValueW"
  c_RegSetValue :: PKEY -> LPCTSTR -> DWORD -> LPCTSTR -> Int -> IO ErrCode


type RegValueType = DWORD

#{enum RegValueType,
 , rEG_BINARY           = REG_BINARY
 , rEG_DWORD            = REG_DWORD
 , rEG_DWORD_LITTLE_ENDIAN = REG_DWORD_LITTLE_ENDIAN
 , rEG_DWORD_BIG_ENDIAN = REG_DWORD_BIG_ENDIAN
 , rEG_EXPAND_SZ        = REG_EXPAND_SZ
 , rEG_LINK             = REG_LINK
 , rEG_MULTI_SZ         = REG_MULTI_SZ
 , rEG_NONE             = REG_NONE
 , rEG_RESOURCE_LIST    = REG_RESOURCE_LIST
 , rEG_SZ               = REG_SZ
 }

-- regSetValueEx has a somewhat wieldly interface if all you want to do is
-- add a string value (a Common Thing to want to do), so we support this
-- specially:
regSetStringValue :: HKEY -> String -> String -> IO ()
regSetStringValue hk key val =
  withTString val $ \ v ->
  regSetValueEx hk key rEG_SZ v (length val * sizeOf (undefined::TCHAR))

regSetValueEx :: HKEY -> String -> RegValueType -> LPTSTR -> Int -> IO ()
regSetValueEx key subkey ty value value_len =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  failUnlessSuccess "RegSetValueEx" $
    c_RegSetValueEx p_key c_subkey 0 ty value value_len
foreign import stdcall unsafe "windows.h RegSetValueExW"
  c_RegSetValueEx :: PKEY -> LPCTSTR -> DWORD -> RegValueType -> LPTSTR -> Int -> IO ErrCode

regUnLoadKey :: HKEY -> String -> IO ()
regUnLoadKey key subkey =
  withForeignPtr key $ \ p_key ->
  withTString subkey $ \ c_subkey ->
  failUnlessSuccess "RegUnLoadKey" $ c_RegUnLoadKey p_key c_subkey
foreign import stdcall unsafe "windows.h RegUnLoadKeyW"
  c_RegUnLoadKey :: PKEY -> LPCTSTR -> IO ErrCode